Improved description of 11.4.1-4.a-5.

The previous description of the 11.4.1-4.a-5 test case implied that an environment object could not be deleted while inside a with. However, the actual test was to test whether the variable declaration could be deleted. The description has been updated to better reflect this.

test/language/expressions/delete/11.4.1-4.a-5.js

@@ -10,14 +10,14 @@ info: >
     language provides no way to directly exercise [[Delete]], the tests are placed here.
 es5id: 11.4.1-4.a-5
 description: >
-    delete operator returns false when deleting the environment object
+    delete operator returns false when deleting the declaration of the environment object
     inside 'with'
 flags: [noStrict]
 includes: [runTestCase.js]
 ---*/
 
 function testcase() {
-  o = new Object();
+  var o = new Object();
   o.x = 1;
   var d;
   with(o)